scholarly journals Suppressors of a Saccharomyces cerevisiae pkc1 mutation identify alleles of the phosphatase gene PTC1 and of a novel gene encoding a putative basic leucine zipper protein.

Genetics ◽  
1995 ◽  
Vol 141 (4) ◽  
pp. 1275-1285 ◽  
Author(s):  
K N Huang ◽  
L S Symington
Keyword(s):  
Protein Kinase ◽  
Leucine Zipper ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Gene Encoding ◽  
Basic Leucine Zipper ◽  
Mapk Cascades ◽  
Synthetically Lethal

Abstract The PKC1 gene product, protein kinase C, regulates a mitogen-activated protein kinase (MAPK) cascade, which is implicated in cell wall metabolism. Previously, we identified the pkc1-4 allele in a screen for mutants with increased rates of recombination, indicating that PKC1 may also regulate DNA metabolism. The pkc1-4 allele also conferred a temperature-sensitive (ts) growth defect. Extragenic suppressors were isolated that suppress both the ts and hyperrecombination phenotypes conferred by the pkc1-4 mutation. Eight of these suppressors for into two complementation groups, designated KCS1 and KCS2. KCS1 was cloned and found to encode a novel protein with homology to the basic leucine zipper family of transcription factors. KCS2 is allelic with PTC1, a previously identified type 2C serine/threonine protein phosphatase. Although mutation of either KCS1 or PTC1 causes little apparent phenotype, the kcs1 delta ptc1 delta double mutant fails to grow at 30 degrees. Furthermore, the ptc1 deletion mutation is synthetically lethal in combination with a mutation in MPK1, which encodes a MAPK homologue proposed to act in the PKC1 pathway. Because PTC1 was initially isolated as a component of the Hog1p MAPK pathway, it appears that these two MAPK cascades share a common regulatory feature.

scholarly journals NHP6A and NHP6B, which encode HMG1-like proteins, are candidates for downstream components of the yeast SLT2 mitogen-activated protein kinase pathway.

1994 ◽  
Vol 14 (4) ◽  
pp. 2391-2403 ◽  
Author(s):  
C Costigan ◽  
D Kolodrubetz ◽  
M Snyder
Keyword(s):  
Protein Kinase ◽  
Synthetic Lethality ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Mitogen Activated Protein ◽  
Multiple Copies ◽  
Delta Cells

The yeast SLK1 (BCK1) gene encodes a mitogen-activated protein kinase (MAPK) activator protein which functions upstream in a protein kinase cascade that converges on the MAPK Slt2p (Mpk1p). Dominant alleles of SLK1 have been shown to bypass the conditional lethality of a protein kinase C mutation, pkc1-delta, suggesting that Pkc1p may regulate Slk1p function. Slk1p has an important role in morphogenesis and growth control, and deletions of the SLK1 gene are lethal in a spa2-delta mutant background. To search for genes that interact with the SLK1-SLT2 pathway, a synthetic lethal suppression screen was carried out. Genes which in multiple copies suppress the synthetic lethality of slk1-1 spa2-delta were identified, and one, the NHP6A gene, has been extensively characterized. The NHP6A gene and the closely related NHP6B gene were shown previously to encode HMG1-like chromatin-associated proteins. We demonstrate here that these genes are functionally redundant and that multiple copies of either NHP6A or NHP6B suppress slk1-delta and slt2-delta. Strains from which both NHP6 genes were deleted (nhp6-delta mutants) share many phenotypes with pkc1-delta, slk1-delta, and slt2-delta mutants. nhp6-delta cells display a temperature-sensitive growth defect that is rescued by the addition of 1 M sorbitol to the medium, and they are sensitive to starvation. nhp6-delta strains also exhibit a variety of morphological and cytoskeletal defects. At the restrictive temperature for growth, nhp6-delta mutant cells contain elongated buds and enlarged necks. Many cells have patches of chitin staining on their cell surfaces, and chitin deposition is enhanced at the necks of budded cells. nhp6-delta cells display a defect in actin polarity and often accumulate large actin chunks. Genetic and phenotypic analysis indicates that NHP6A and NHP6B function downstream of SLT2. Our results indicate that the Slt2p MAPK pathway in Saccharomyces cerevisiae may mediate its function in cell growth and morphogenesis, at least in part, through high-mobility group proteins.

scholarly journals BRO1, a novel gene that interacts with components of the Pkc1p-mitogen-activated protein kinase pathway in Saccharomyces cerevisiae.

1996 ◽  
Vol 16 (6) ◽  
pp. 2585-2593 ◽  
Author(s):  
M E Nickas ◽  
M P Yaffe
Keyword(s):  
Protein Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Yeast Cells ◽  
Growth Defect ◽  
Binding Motif ◽  
Temperature Sensitive ◽  
Cell Integrity ◽  
Gene Encoding ◽  
Mitogen Activated Protein ◽  
Kinase Pathway

Yeast cells with mutations in BRO1 display phenotypes similar to those caused by deletion of BCK1, a gene encoding a MEK kinase that functions in a mitogen-activated protein kinase pathway mediating maintenance of cell integrity. bro1 cells exhibit a temperature-sensitive growth defect that is suppressed by the addition of osmotic stabilizers or Ca2+ to the growth medium or by additional copies of the BCK1 gene. At permissive temperatures, bro1 mutants are sensitive to caffeine and respond abnormally to nutrient limitation. A null mutation in BRO1 is synthetically lethal with null mutations in BCK1, MPK1, which encodes a mitogen-activated protein kinase that functions downstream of Bck1p, or PKC1, a gene encoding a protein kinase C homolog that activates Bck1p. Analysis of the isolated BRO1 gene revealed that it encodes a novel, 97-kDa polypeptide which contains a putative SH3 domain-binding motif and is homologous to a protein of unknown function in Caenorhabditis elegans.

NHP6A and NHP6B, which encode HMG1-like proteins, are candidates for downstream components of the yeast SLT2 mitogen-activated protein kinase pathway

1994 ◽  
Vol 14 (4) ◽  
pp. 2391-2403
Author(s):  
C Costigan ◽  
D Kolodrubetz ◽  
M Snyder
Keyword(s):  
Protein Kinase ◽  
Synthetic Lethality ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Mitogen Activated Protein ◽  
Multiple Copies ◽  
Delta Cells

The yeast SLK1 (BCK1) gene encodes a mitogen-activated protein kinase (MAPK) activator protein which functions upstream in a protein kinase cascade that converges on the MAPK Slt2p (Mpk1p). Dominant alleles of SLK1 have been shown to bypass the conditional lethality of a protein kinase C mutation, pkc1-delta, suggesting that Pkc1p may regulate Slk1p function. Slk1p has an important role in morphogenesis and growth control, and deletions of the SLK1 gene are lethal in a spa2-delta mutant background. To search for genes that interact with the SLK1-SLT2 pathway, a synthetic lethal suppression screen was carried out. Genes which in multiple copies suppress the synthetic lethality of slk1-1 spa2-delta were identified, and one, the NHP6A gene, has been extensively characterized. The NHP6A gene and the closely related NHP6B gene were shown previously to encode HMG1-like chromatin-associated proteins. We demonstrate here that these genes are functionally redundant and that multiple copies of either NHP6A or NHP6B suppress slk1-delta and slt2-delta. Strains from which both NHP6 genes were deleted (nhp6-delta mutants) share many phenotypes with pkc1-delta, slk1-delta, and slt2-delta mutants. nhp6-delta cells display a temperature-sensitive growth defect that is rescued by the addition of 1 M sorbitol to the medium, and they are sensitive to starvation. nhp6-delta strains also exhibit a variety of morphological and cytoskeletal defects. At the restrictive temperature for growth, nhp6-delta mutant cells contain elongated buds and enlarged necks. Many cells have patches of chitin staining on their cell surfaces, and chitin deposition is enhanced at the necks of budded cells. nhp6-delta cells display a defect in actin polarity and often accumulate large actin chunks. Genetic and phenotypic analysis indicates that NHP6A and NHP6B function downstream of SLT2. Our results indicate that the Slt2p MAPK pathway in Saccharomyces cerevisiae may mediate its function in cell growth and morphogenesis, at least in part, through high-mobility group proteins.

scholarly journals Mitogen-activated protein kinases associated sites of tobacco REPRESSION OF SHOOT GROWTH regulates its localization in plant cells

2021 ◽  
Author(s):  
Luyao Wang ◽  
Ying Gui ◽  
Bingye Yang ◽  
Fangjie Si ◽  
Jianhua Guo ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Plant Defense ◽  
Shoot Growth ◽  
Leucine Zipper ◽  
Intracellular Localization ◽  
Phosphorylation Site ◽  
Feedback Regulation ◽  
Mitogen Activated Protein Kinase ◽  
Basic Leucine Zipper ◽  
Mitogen Activated Protein

Plant defense and growth rely on multiple transcriptional factors (TFs). REPRESSION OF SHOOT GROWTH (RSG) is known as one of the important TFs in tobacco (Nicotiana tabacum) with a basic leucine zipper domain. RSG was involved in plant gibberellin feedback regulation by inducing the expression of key genes. The tobacco calcium-dependent protein kinase, CDPK1 was reported to interact with RSG and manipulate its intracellular localization by phosphorylating Ser-114 of RSG. Here, we identified tobacco mitogen-activated protein kinase 3 (NtMPK3) as a RSG interacted protein kinase. Mutation of predicted MAPK-associated phosphorylation site of RSG (Thr-30, Ser-74 and Thr-135) significantly altered the intracellular localization of NtMPK3-RSG interaction complex. Nuclear transport of RSG and its amino acids mutants (T30A and S74A) were observed after treated with plant defense elicitor peptide flg22 in 5 min, while the two mutated RSG swiftly relocalized in tobacco cytoplasm in 30 min. Moreover, triple points mutation of RSG (T30A/S74A/T135A) mimics constant unphosphorylated status, and predominantly localized in tobacco cytoplasm. RSG (T30A/S74A/T135A) showed no relocalization effect under the treatments of either flg22, B. cereus AR156 or GA3, and was impaired in its role as TFs. Our results suggest that MAPK associated phosphorylation sites of RSG regulate its localization in tobacco and constant unphosphorylation of RSG in Thr-30, Ser-74 and Thr-135 keeps RSG predominantly localized in cytoplasm.

scholarly journals Glucocorticoid-Induced Leucine Zipper Inhibits the Raf-Extracellular Signal-Regulated Kinase Pathway by Binding to Raf-1

2002 ◽  
Vol 22 (22) ◽  
pp. 7929-7941 ◽  
Author(s):  
Emira Ayroldi ◽  
Ornella Zollo ◽  
Antonio Macchiarulo ◽  
Barbara Di Marco ◽  
Cristina Marchetti ◽  
...  
Keyword(s):  
T Cell ◽  
Protein Kinase ◽  
T Cell Activation ◽  
Leucine Zipper ◽  
Nuclear Translocation ◽  
Mapk Pathway ◽  
Interleukin 2 ◽  
Mitogen Activated Protein Kinase ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal

ABSTRACT Glucocorticoid-induced leucine zipper (GILZ) is a leucine zipper protein, whose expression is augmented by dexamethasone (DEX) treatment and downregulated by T-cell receptor (TCR) triggering. Stable expression of GILZ in T cells mimics some of the effects of glucocorticoid hormones (GCH) in GCH-mediated immunosuppressive and anti-inflammatory activity. In fact, GILZ overexpression inhibits TCR-activated NF-κB nuclear translocation, interleukin-2 production, FasL upregulation, and the consequent activation-induced apoptosis. We have investigated the molecular mechanism underlying GILZ-mediated regulation of T-cell activation by analyzing the effects of GILZ on the activity of mitogen-activated protein kinase (MAPK) family members, including Raf, MAPK/extracellular signal-regulated kinase (ERK) 1/2 (MEK-1/2), ERK-1/2, and c-Jun NH2-terminal protein kinase (JNK). Our results indicate that GILZ inhibited Raf-1 phosphorylation, which resulted in the suppression of both MEK/ERK-1/2 phosphorylation and AP-1-dependent transcription. We demonstrate that GILZ interacts in vitro and in vivo with endogenous Raf-1 and that Raf-1 coimmunoprecipitated with GILZ in murine thymocytes treated with DEX. Mapping of the binding domains and experiments with GILZ mutants showed that GILZ binds the region of Raf interacting with Ras through the NH2-terminal region. These data suggest that GILZ contributes, through protein-to-protein interaction with Raf-1 and the consequent inhibition of Raf-MEK-ERK activation, to regulating the MAPK pathway and to providing a further mechanism underlying GCH immunosuppression.

scholarly journals PDK1 Homologs Activate the Pkc1–Mitogen-Activated Protein Kinase Pathway in Yeast

1999 ◽  
Vol 19 (12) ◽  
pp. 8344-8352 ◽  
Author(s):  
Maiko Inagaki ◽  
Tobias Schmelzle ◽  
Kyoko Yamaguchi ◽  
Kenji Irie ◽  
Michael N. Hall ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mapk Pathway ◽  
Phosphorylation Site ◽  
Genetic Selection ◽  
Mitogen Activated Protein Kinase ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Mutant Form ◽  
Mitogen Activated Protein

ABSTRACT PDK1 (phosphoinositide-dependent kinase 1) is a mammalian growth factor-regulated serine/threonine kinase. Using a genetic selection based on a mutant form of the yeast MAP kinase kinase Ste7, we isolated a gene, PKH2, encoding a structurally and functionally conserved yeast homolog of PDK1. Yeast cells lacking bothPKH2 and PKH1, encoding another PDK1 homolog, were nonviable, indicating that Pkh1 and Pkh2 share an essential function. A temperature-sensitive mutant, pkh1D398Gpkh2, was phenotypically similar to mutants defective in the Pkc1–mitogen-activated protein kinase (MAPK) pathway. Genetic epistasis analyses, the phosphorylation of Pkc1 by Pkh2 in vitro, and reduced Pkc1 activity in the pkh1D398G pkh2mutant indicate that Pkh functions upstream of Pkc1. The Pkh2 phosphorylation site in Pkc1 (Thr-983) is part of a conserved PDK1 target motif and essential for Pkc1 function. Thus, the yeast PDK1 homologs activate Pkc1 and the Pkc1-effector MAPK pathway.

scholarly journals Role for RACK1 Orthologue Cpc2 in the Modulation of Stress Response in Fission Yeast

2009 ◽  
Vol 20 (18) ◽  
pp. 3996-4009 ◽  
Author(s):  
Andrés Núñez ◽  
Alejandro Franco ◽  
Marisa Madrid ◽  
Teresa Soto ◽  
Jero Vicente ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Fission Yeast ◽  
Mammalian Cells ◽  
Mapk Pathway ◽  
Ribosomal Subunit ◽  
Mitogen Activated Protein Kinase ◽  
Specific Gene ◽  
Cell Integrity ◽  
Mapk Cascades ◽  
Mitogen Activated Protein

The receptor of activated C kinase (RACK1) is a protein highly conserved among eukaryotes. In mammalian cells, RACK1 functions as an adaptor to favor protein kinase C (PKC)-mediated phosphorylation and subsequent activation of c-Jun NH2-terminal kinase mitogen-activated protein kinase. Cpc2, the RACK1 orthologue in the fission yeast Schizosaccharomyces pombe, is involved in the control of G2/M transition and interacts with Pck2, a PKC-type protein member of the cell integrity Pmk1 mitogen-activated protein kinase (MAPK) pathway. Both RACK1 and Cpc2 are structural components of the 40S ribosomal subunit, and recent data suggest that they might be involved in the control of translation. In this work, we present data supporting that Cpc2 negatively regulates the cell integrity transduction pathway by favoring translation of the tyrosine-phosphatases Pyp1 and Pyp2 that deactivate Pmk1. In addition, Cpc2 positively regulates the synthesis of the stress-responsive transcription factor Atf1 and the cytoplasmic catalase, a detoxificant enzyme induced by treatment with hydrogen peroxide. These results provide for the first time strong evidence that the RACK1-type Cpc2 protein controls from the ribosome the extent of the activation of MAPK cascades, the cellular defense against oxidative stress, and the progression of the cell cycle by regulating positively the translation of specific gene products involved in key biological processes.

scholarly journals MITOGEN ACTIVATED PROTEIN KINASE: FUNCTION AND RESPONSES TO DIFFERENT STRESSES IN PLANTS

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Sara Khan ◽  
Nadia Iqbal ◽  
Farah Deeba ◽  
Raheela Jabeen
Keyword(s):  
Protein Kinase ◽  
Map Kinases ◽  
Mapk Pathway ◽  
Ultra Violet ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Ultra Violet Radiation ◽  
Mapk Cascades ◽  
Mitogen Activated Protein ◽  
Regulation Functions

Mitogen Activated Protein Kinase (MAPK) pathway is the most commonly studied signaling mechanisms, consisting of different groups of protein kinases that participate in regularly connecting interpretation of external stimuli that can change in gene expression or cellular organization within eukaryotic systems. The MAP kinase pathways functions in plants cell signaling (intra- and extra). MAPK cascades follow a response system. MAP kinases are the component of kinase constituents that deliver signals from sensors to responders in eukaryotes including plants. Several pathways are activated under different environmental stresses. Stimulating agents may be biological (biotic) like microbial infections or environmental (abiotic) like temperatures threshold, high salt concentration, drought, heavy metal, Ultra-violet radiation, ozone gases and reactive oxygen species (ROS). The involvement of MAPK signaling pathway in different stresses has been widely studied. In this review we also try to highlight MAPK cascades, its regulation, functions and recent findings in various cellular processes against stress conditions.

scholarly journals Expression of transgenes enriched in rare codons is enhanced by the MAPK pathway

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jackson Peterson ◽  
Siqi Li ◽  
Erin Kaltenbrun ◽  
Ozgun Erdogan ◽  
Christopher M. Counter
Keyword(s):  
Amino Acids ◽  
Protein Kinase ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Rare Codons ◽  
Synonymous Codons ◽  
Multiple Components ◽  
Human Genes ◽  
Regulatory Module ◽  
Mitogen Activated Protein

AbstractThe ability to translate three nucleotide sequences, or codons, into amino acids to form proteins is conserved across all organisms. All but two amino acids have multiple codons, and the frequency that such synonymous codons occur in genomes ranges from rare to common. Transcripts enriched in rare codons are typically associated with poor translation, but in certain settings can be robustly expressed, suggestive of codon-dependent regulation. Given this, we screened a gain-of-function library for human genes that increase the expression of a GFPrare reporter encoded by rare codons. This screen identified multiple components of the mitogen activated protein kinase (MAPK) pathway enhancing GFPrare expression. This effect was reversed with inhibitors of this pathway and confirmed to be both codon-dependent and occur with ectopic transcripts naturally coded with rare codons. Finally, this effect was associated, at least in part, with enhanced translation. We thus identify a potential regulatory module that takes advantage of the redundancy in the genetic code to modulate protein expression.

scholarly journals Exercise-induced mitogen-activated protein kinase signalling in skeletal muscle

2004 ◽  
Vol 63 (2) ◽  
pp. 227-232 ◽  
Author(s):  
Yun Chau Long ◽  
Ulrika Widegren ◽  
Juleen R. Zierath
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Muscle Contraction ◽  
Mitogen Activated Protein Kinase ◽  
Mapk Cascades ◽  
Extracellular Signal ◽  
Mapk Signalling ◽  
Mitogen Activated Protein ◽  
Exercise Induced ◽  
Response To Exercise

Exercise training improves glucose homeostasis through enhanced insulin sensitivity in skeletal muscle. Muscle contraction through physical exercise is a physiological stimulus that elicits multiple biochemical and biophysical responses and therefore requires an appropriate control network. Mitogen-activated protein kinase (MAPK) signalling pathways constitute a network of phosphorylation cascades that link cellular stress to changes in transcriptional activity. MAPK cascades are divided into four major subfamilies, including extracellular signal-regulated kinases 1 and 2, p38 MAPK, c-Jun NH2-terminal kinase and extracellular signal-regulated kinase 5. The present review will present the current understanding of parallel MAPK signalling in human skeletal muscle in response to exercise and muscle contraction, with an emphasis on identifying potential signalling mechanisms responsible for changes in gene expression.

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